Conclusions Microbial tests to detect inhibitors in milk are not suit-able for monitoring the presence of antibiotic residues ingoats’ colostrum as a high percentage of “false positives”in testing of secretions until 24 h post-partum is obtained.Moreover, the occurrence of positive or “non-compliant”results is mainly related to the effect of post-partum hoursand the high protein content of colostrum. The presence ofgoats’ colostrum to raw milk affects more the response ofthe BRT MRL than Delvotest SP-NT MCS and Eclipse 100,especially with colostrum obtained shortly after partum(12 and 24 h). Therefore, to avoid the interference causedby the presence of colostrum in milk, it is recommended toadhere to good farming practices concerning animal iden-tification and separation of colostral secretions, especiallyduring the first 48 h after delivery, to prevent colostrum toget mixed with the milk which can cause “non-compliant”results in microbial tests to detect inhibitors.